The inventive concepts described herein relate to a nonvolatile memory device, a memory system including the nonvolatile memory device, and/or an external power control method.
Semiconductor memory devices may be volatile or nonvolatile. A nonvolatile semiconductor memory device may retain data stored therein even at power-off. The nonvolatile memory device may be permanent or reprogrammable, depending upon the fabrication technology used. The nonvolatile memory device may be used for user data, program, and microcode storage in a wide variety of applications in the computer, avionics, telecommunications, and consumer electronics industries. A nonvolatile memory device often utilizes an external supply voltage, however, a typical nonvolatile memory device may not detect a drop in voltage level of the supply voltage and control an internal circuit according to the detection result. Which may result in problems in reliably operating the nonvolatile memory device.